When using a plurality of ventilators, for example for the ventilation of buildings, there is a need to centrally control the ventilators. In order to do this, the ventilators are connected to one another via a network. In order to efficiently communicate with the individual ventilators in the network, each ventilator must be assigned a unique address in the network.
For this purpose, in a conventional process, the ventilators are manually switched on, one by one, each newly activated ventilator being assigned a unique address before the next ventilator can be switched on. This is repeated until all of the ventilators connected in the network are individually addressable. This kind of method has the disadvantage of requiring many manual switching operations in the installation before all ventilators can be individually communicated with a central control unit via the network.
From DE 10 2004 039 447 A1, a method is known for the automatic assignment of addresses by a master to participants in a system, wherein each participant has an adjustable address memory and is ready-to-receive via a predetermined channel, and wherein, at the beginning of the process, each participant chooses a random address. With this method, the master checks, for the entire valid address space, whether two participants have by coincidence chosen the same random address, and if that is the case, causes each participant to choose a new random address, the previously selected unique addresses of the participants being eliminated as potential new random addresses. This method has the disadvantage that the address space can be very large, particularly in large networks with many participants, and thus a relatively long time passes until the master has queried the entire address space, and each participant possesses a valid individual address.
This invention is therefore based on the task of devising a method of assigning network addresses to ventilators that will make it possible to assign network addresses to the ventilators automatically, as quickly as possible, even in large networks with many participants.
With a method of the kind described above, this task is inventively performed by the control unit assigning all ventilators an identical start-address as a network address at the beginning of the process and sending serial number queries with a serial number mask to the start-address, the serial number mask being comprised of definite and indefinite positions, and the ventilators responding to the serial number mask subject to their serial number, the control unit, depending on the responses from the ventilators, assigning unique addresses and/or modifying the serial number mask for further serial number queries. This has the advantage that the control unit does not have to search the entire address space, or as the case may be, the entire serial number space, in order to identify all ventilators and/or in order to assign them a unique network address.
In one embodiment of the invention, each ventilator whose serial number matches the definite positions of the serial number mask of the serial number query in the same positions responds to the serial number query with its complete serial number. In this way, the control unit can definitely identify the ventilators and administer a table in the memory containing the serial numbers of the ventilators in the network and the network addresses that match them. These serial numbers and network addresses can be accessed by a service technician by means of a display or other output element.
In an additional embodiment of the invention, the control unit, when it receives an error-free response from the ventilator, assigns the ventilator, based on the serial number received, by means of an address assignment command, a unique network address and repeats, after assigning a network address via an address assignment command, the previous serial number query with the same serial number mask in order to identify additional ventilators whose serial numbers fit the serial number mask and assigns them unique network addresses. This is particularly advantageous when the network interface of the ventilators detects a transmission of another participant on the bus and therefore suppresses its response in order to prevent a collision, or when the complete response of a first ventilator is overlaid by a response with the higher signal level of another ventilator. By repeating the serial number query, it is ensured that each serial number that matches the serial number mask is detected and that the respective ventilator can be assigned a unique network address.
In an additional embodiment of an inventive method, the control unit, when it receives an invalid response, sends another serial number query with a modified serial number mask to the start-address, whereby the control unit transforms the next indefinite position of the serial number mask, in the order of significance, into a definite position. This is advantageous, because ventilators are usually produced and sold with ascending serial numbers. When launching a new installation with many ventilators, the serial numbers of the ventilators used will normally lie close together, so that they differ only in the low-order positions of the serial numbers. Because the low-order positions are, to start with, the definite positions, the number of possible collisions between responses is minimized, and all ventilators are identified as quickly as possible by means of their different serial numbers, because as a rule, the higher-order positions are not suitable for distinguishing between ventilators and are masked out by the indefinite positions of the serial number mask.
Preferably, in one embodiment of the invention, the control unit, when there is no response, sends a further serial number query with a modified serial number mask to the start-address, whereby the control unit increases the highest-order definite position of the serial number mask by one character in the serial number alphabet and, if the last character in the alphabet is reached at the highest-order definite position of the serial number mask, and the serial number mask does not have only one definite position, the control unit transforms the highest-order definite position of the serial number mask into an indefinite position.
This embodiment has the advantage that every possible serial number character of the serial number alphabet is queried for the respective definite position of the serial number mask, and if a definite position is no longer needed for further discrimination, it will be transformed once again into an indefinite position in the serial mask, in order to minimize the number of serial number queries required.
The same objects are designated with the same reference signs in the different figures.